Electronic camera, image processing apparatus, image processing method and image processing computer program

ABSTRACT

An electronic camera detects a person&#39;s face image from an object image obtained by photographing an object, executes an enlarging process on the detected face image so as to obtain a face image whose face size is suitable, and displays the face image which is enlarged into the suitable size on a display device. When a plurality of people are present on the object image, the enlarged face images are switched by an image operating switch. As a result, the switched face image is displayed on the display device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromprior Japanese Patent Application No. 2005-319868, filed Nov. 2, 2005,the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electronic camera, an imageprocessing apparatus, and image processing method and an imageprocessing computer program. More specifically, the invention relates toa technique for recognizing a photographed face image of an object.

2. Description of the Related Art

In electronic cameras, photographed images of objects can be checked onscreens such as liquid crystal monitors provided on the rear surfaces ofthe cameras. As a result, in the case where an object is a person, afacial expression at the time of photographing can be checked.

As a technique for extracting a person's face, for example, Jpn. Pat.Appln. KOKAI Publication No. 8-63597 discloses a method of determining aface candidate region corresponding to a shape of a person's face anddetermining a face region from the feature quantity in the facecandidate region so as to extract the person's face from a colororiginal image.

As a unit that checks face images, for example, Jpn. Pat. Appln. KOKAIPublication No. 2004-240829 discloses a technique for detecting an edgefrom face portrait image data developed in a memory, extracting a pairof edges as candidates of both eyes, narrowing the candidates accordingto the feature of the person's face, estimating a face region in thefacial portrait image data from the narrowed position of both eyes,obtaining a correcting amount from an average value of luminance in theestimated face region, and correcting the facial portrait image dataaccording to the correcting amount so as to adjust brightness of thefacial portrait image data.

Jpn. Pat. Appln. KOKAI Publication No. 6-217187 discloses a techniquefor adjusting a zoom so that the size of a face portion of an imagebecomes uniform so as to obtain a stable image even when an objectmoves.

Jpn. Pat. Appln. KOKAI Publication No. 2003-323615 discloses a techniquefor accepting a person's face image as a sample image, detecting aregion in the vicinity of the face on the image input using a feature ofthe input sample image, displaying candidates of the detected region inthe vicinity of the face on the image, and inputting a narrowingcondition for the displayed candidate of the area in the vicinity of theface as to whether the displayed image is a face image so as to executea face detecting process.

On the other hand, Jpn. Pat. Appln. KOKAI Publication Nos. 5-268513,9-233384 and 11-84481 disclose techniques for, when a person's faceimage displayed on a screen is small, enlarging the face image by meansof cropping so as to display it on the monitor screen.

BRIEF SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide anelectronic camera that has a simple interface for, when a plurality offaces as objects are on an image, checking respective faces and goodphotographed state.

Therefore, according to the present invention, there is provided anelectronic camera comprising an image processing section which, when aplurality of people are present in an object image, recognizes faceimages from the object image; an image operating section which acceptsan instruction for sequentially switching the face images to bedisplayed on a display section; and a control section which controls theface images so that they are enlarged and sequentially switched to bedisplayed on the display section according to the instruction acceptedby the image operating section.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention, andtogether with the general description given above and the detaileddescription of the embodiments given below, serve to explain theprinciples of the invention.

FIG. 1 is a block diagram illustrating a schematic constitution of anelectronic camera according to a first embodiment of the presentinvention;

FIG. 2A is a block diagram illustrating a schematic constitution of theelectronic camera according to a modified example 1 of a modification ofthe present invention;

FIG. 2B is a block diagram illustrating a schematic constitution of theelectronic camera according to a modified example 2 of a modification ofthe present invention;

FIG. 3 is a rear view viewed from a rear side of the electronic cameraillustrating the constitution of the electronic camera according to afirst embodiment of the present invention;

FIG. 4 is a flowchart explaining an operation for checking a face imagein the electronic camera according to the first embodiment of thepresent invention;

FIG. 5 is a diagram illustrating examples of object images and regionsof interest to be displayed on a liquid crystal display 60 in a displaydevice of FIG. 1;

FIG. 6A is a diagram illustrating an example of superimposed display ofthe enlarged image in a region of interest 72 b of FIG. 5, an imageframe and a display region;

FIG. 6B is a diagram illustrating an example of a superimposed displayof the enlarged image in a region of interest 72 c of FIG. 5, an imageframe and a display region;

FIG. 6C is a diagram illustrating an example of superimposed display ofthe enlarged image in a region of interest 72 a of FIG. 5, an imageframe and a display region;

FIG. 6D is a diagram illustrating an example of superimposed display ofthe enlarged image in a region of interest 72 e of FIG. 5, an imageframe and a display region;

FIG. 6E is a diagram illustrating an example of superimposed display ofthe enlarged image in a region of interest 72 d of FIG. 5, an imageframe and a display region;

FIG. 7 is a diagram illustrating a constitutional example of an objectswitching button according to a first modified example in the firstembodiment of the present invention;

FIG. 8 is a rear view viewed from the rear side of the electronic cameraillustrating a constitution of the electronic camera according to thefirst modified example in the first embodiment of the present invention;

FIG. 9 is a flowchart explaining an operation for checking a face imagein the electronic camera according to the first modified example in thefirst embodiment of the present invention;

FIG. 10 is a flowchart explaining the operation for checking a faceimage in the electronic camera according to a second modified example inthe first embodiment of the present invention;

FIG. 11 is a diagram illustrating an example where an object imageobtained by the electronic camera is divided into small regionsaccording to the second modified example in the first embodiment of thepresent invention;

FIG. 12 is a flowchart explaining the operation for checking a faceimage in the electronic camera according to a second embodiment of thepresent invention;

FIG. 13 is a flowchart explaining the operation for checking the faceimage in the electronic camera according to a third embodiment of thepresent invention; and

FIG. 14 is a flowchart explaining the operation for checking the faceimage in the electronic camera according to a modified example in thethird embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention will be explained below withreference to the drawings.

FIRST EMBODIMENT

FIG. 1 is a block diagram illustrating a schematic constitution of anelectronic camera according to a first embodiment of the presentinvention.

In FIG. 1, a system controller 10 is control means for controlling acontrol operation of the entire electronic camera, and is composed of aCPU or the like. The system controller 10 is connected to aphotographing lens 12 which is built into a lens barrel, not shown, aCCD 14 as an imaging element which images an optical image of an objectvia the photographing lens 12, an imaging circuit 16 which converts theoptical image captured by the CCD 14 into an electrical signal, ananalog-to-digital converter 18, a signal processing circuit 20 and amemory 22. Further, the system controller 10 is connected to a distancemeasuring unit 34, a release switch (SW) 38, a menu switch (SW) 40, animage operating switch (SW) 42 and an operating switch (SW) 44. Thememory 22 is connected to a storage media 30 via a compressing circuit28 and to a display device 32 via a display memory 26.

The distance measuring unit 34 is for obtaining a focussing position ofan object (not shown) according to automatic measurement of distance.The release switch 38 corresponds to a release button 52, mentionedlater, for starting a photographing operation, and has a two-tieredconstitution including a first release switch and a second releaseswitch. When the release button 52 is half-pressed down, the firstrelease switch is in an ON state so that photographing preparingoperations such as a photometry process and a distance measuring processare performed. When the release button 52 is fully pressed down, thesecond release switch is turned on, so that an exposing operation isexecuted.

The menu switch 40 is for operating various functions of the electroniccamera. The image operating switch 42 is for switching an image to bedisplayed on the display device 32. The image operating switch 42 iscomposed of a face image browsing mode switch 58, an image switchingbutton 60, an object switching button 62 and the like, mentioned later.When these buttons are operated, an image to be displayed on the displaysurface of the display device 32 is switched. The operating switch 44corresponds to an operating button such as a power switch necessary foroperating the camera.

The photographing lens 12, the CCD 14, the imaging circuit 16, theanalog-to-digital converter 18, the signal processing circuit 20, thememory 22, the display memory 26, the compressing circuit 28, thestorage media 30, the display device 32, the distance measuring unit 34are well known. For this reason, their details are omitted.

In such a constitution, an optical image of an object which passesthrough the photographing lens 12 is converted into an electric signalby the CCD 14, and the electric signal is converted into an analog imagesignal by the imaging circuit 16. The analog image signal is convertedinto a digital image signal (hereinafter, “image information”) by theanalog-to-digital converter 18, and a process for converting colorinformation of the image information, a pixel count converting process,a process for recognizing a face image and the like are executed in thesignal processing circuit 20. The image information which is subject tovarious image processes by the signal processing circuit 20 is stored inthe nonvolatile memory 22. The memory 22 is composed of a high-speedstorage unit, for example, SDRAM, and is used also as a work area for animage process, mentioned later.

The image information which is once stored in the memory 22 iscompressed into JPEG format, for example, by the compressing circuit 28,and is stored in the storage media 30 such as smart media (registeredtrademark). The image signal which is subject to the signal process istransferred from the memory 22 to the display memory 26, and isdisplayed on the display device 32 via a driving circuit, not shown.

When the image stored in the storage media 30 is displayed, the storedimage is decompressed by an expanding circuit, not shown, and after theimage is subject to a predetermined image process by the signalprocessing circuit 20, the image is displayed on the display device 32similarly to the photographing case.

FIG. 3 is a rear view viewed from a rear side of the electronic cameraillustrating a constitution of the electronic camera according to thefirst embodiment of the present invention.

In FIG. 3, the release button 52 corresponding to the release switch 38,and a photographing mode switch 54 for selecting a photographing modeare provided above a camera main body 50 a. A liquid crystal display 60as the display device 32 is provided to an approximately center of arear side of the camera main body 50 a.

A face image browsing mode switch 62 for operating a face image browsingmode whose details are mentioned later is provided to the left side ofthe liquid crystal display 60. On the other hand, the right side of theliquid crystal display 60 is provided with an image switching button 64for switching one frame of image currently displayed on the liquidcrystal display 60, and an object switching button 66 for switching toselect an object displayed on the liquid crystal display 60. In thiscase, the image switching button 64 is composed of a switching button 64a for switching an image into an image one frame after the currentlydisplayed image so as to display it, and a switching button 64 b forswitching an image into an image one frame before the current displayedimage so as to display it.

With reference to the flowchart in FIG. 4, an operation for checking aface image in the electronic camera according to the first embodiment isexplained below.

When a power switch, not shown, is turned on, an object is photographedin step S1. In this case, as shown in FIG. 5, a plurality (in this case,five) of people 70 a to 70 e are present in an object image obtained byphotographing objects. When the objects are photographed in step S1, theimage is transmitted from the CCD 14 via the imaging circuit 16 and theanalog-to-digital converter 18 to the signal processing circuit 20 asmentioned above. The signal processing circuit 20 then executes a colorinformation converting process, a pixel count changing process, a faceimage recognizing process and the like in step S2. The face imagerecognizing process is well known, and since its detail is described in,for example, Jpn. Pat. Appln. KOKAI Publication No. 2004-240829, itsexplanation is omitted.

The signal processing circuit 20 determines regions of interest (ROI) asregions according to the face images in step S3. The regions of interestand the number of the objects' faces N1 (=5) are stored in the memory22. For example, an image shown in FIG. 5 is displayed on the liquidcrystal display 50. In this case, the region of interest for the faceimage includes five regions designated by 72 a to 72 e correspondinglyto people 70 a to 70 e. The sizes of the region of interest, coordinatestart positions and the like of these regions are stored in the memory22. Also image information about results of the color informationconverting process and the image count converting process are stored inthe memory 22.

The face image browsing mode switch 62 is pressed down in step S4, andthe face image browsing mode is executed according to the followingsteps. The face image in the region of interest positioned on the upperleft portion of the screen is enlarged to be displayed in the rasterorder based on the contents in the memory 22 in step S5. “1” is set asthe face image N. In this case, as shown in FIG. 5, the region ofinterest 72 b having the higher order in the raster order, namely, theface image of the person 70 b is displayed as an enlarged image 74 b onthe liquid crystal display 60 as shown in FIG. 6A.

At this time, a position on the screen of FIG. 5, which corresponds tothe region of interest 72 b to be displayed as the enlarged image 74 b,is displayed on the liquid crystal display 60 in a superimposing manner.That is to say, a screen frame 76 displayed in the superimposing mannershows the entire screen of the liquid crystal display 60. A displayregion 78 a in the screen frame 76 corresponds to the region of interest72 b in FIG. 5. A user, therefore, can check the enlarged image 74 bshown in FIG. 6A and simultaneously the position on the screen where theenlarged image 74 b is present on the liquid crystal display 60.

Thereafter, the camera is in an input standby state in step S6. A stateof the object switching button 66 is detected in step S7. When theobject switching button 66 is pressed down, the sequence goes to stepS8, but when it is not pressed down, the sequence goes to step S6. Thatis to say, steps S6 and S7 are repeated until the object switchingbutton 66 is pressed down.

On the other hand, when the detection is made in step S7 that the objectswitching button 66 is pressed down, the sequence goes to step S8, sothat a determination is made whether the face image N set in step S5 isN1. In this case, since “1” is set as N in step S5 and “5” is set as thenumber of the object's faces N1 in step S3, the sequence goes to step S9so that N is incremented.

The region of interest related to the face image of the N-numberedobject is enlarged to be displayed on the liquid crystal display 60 instep S11. In this case, since incrementing is carried out in step S9,the face image of N=2 is displayed. That is to say, as shown in FIG. 5,the region of interest 72 c on the second-highest order of the rasterorder, namely, the face image of the person 70 c is displayed as anenlarged image 74 c on the liquid crystal display 60 as shown in FIG.6B. At the same time, a display region 78 c in the screen frame 76corresponding to the region of interest 72 c in FIG. 5 is displayed onthe liquid crystal display 60 in the superimposing manner. Thereafter,the sequence goes to step S6 so that the camera is in the input standbystate.

The processing operations in steps S6 to S9 and S11 are repeated untilN=N1 is established in step S8. That is to say, in the first embodiment,the enlarged image 74 b, the screen frame 76 and the display region 78 a(see FIG. 6A) are displayed on the liquid crystal display 60 firstly.Thereafter, every time when the object switching button 66 is presseddown, the enlarged image 74 c, the screen frame 76 and a display region78 c (see FIG. 6B) are displayed, an enlarged image 74 a, the screenframe 76 and a display region 78 a (see FIG. 6C) are displayed, anenlarged image 74 e, the screen frame 76 and a display region 78 e (seeFIG. 6D) are displayed, and an enlarged image 74 d, the screen frame 76and a display region 78 d (see FIG. 6E) are displayed sequentially onthe liquid crystal display 60.

When N=N1 is established in step S8, the sequence goes to step S10, and“1” is set as N is again. This is because the number of the face imagesof the objects (people) is five in this embodiment, and when the objectswitching button 66 is pressed down four times, the face image of thefifth person is enlarged to be displayed. Therefore, when the objectswitching button 66 is pressed down five times, the first enlargedscreen 74 b is displayed next, and the face image N is again set to “1”in step S10. As a result, the enlarged image 74 b of the N-th object,namely, the first object, the screen frame 76 and the display region 78a are displayed on the liquid crystal display 60 at next step S11.

Since reducing and enlarging processes are executed on image informationin the respective regions of interest, the enlarged images 74 a to 74 eare displayed with the approximately same size on the liquid crystaldisplay 60.

According to the first embodiment, even in the case where a plurality offaces are photographed as objects, the object switching button 66 isoperated, and a plurality of face images are selectively switched so asto be capable of being displayed in the approximately same size.Therefore, the respective faces and a good photographed state are easilychecked.

A position on the photographed image, in which the enlarged imagecurrently displayed on the liquid crystal display 60 is present, can beeasily checked by the screen frame 76 and the display regions 78 a to 78e to be displayed on the liquid crystal display 60.

In the first embodiment, the sizes of the region of interest and thecoordinate start positions are stored, but the present invention is notlimited to this, and thus the center point of the region of interest maybe stored. In this case, the raster order is different from the displayorder in FIG. 6.

In the case where the photographing mode for user's photographing andthe face image browsing mode for browsing the face images in the displaydevice 32 are provided, the processes after step S2 can be executedunder the condition that the face image browsing mode is specified bythe user. In this case, when a detection is made that the face imagebrowsing mode switch 62 is operated, a detection may be made that theface image browsing mode is specified by the user. Step S4 is omitted.

As shown in FIG. 2A, in the case of a modified example where the signalprocessing circuit 46 is added to the constitution, an object image canbe selected from a plurality of images saved in the storage media 30 ata reproducing mode for user's browsing of a photographed object image.That is to say, the object image is selected by the user at thereproducing mode, and the signal processing circuit 46 executes theprocesses after step S2 on the object image selected instead of theobject image from the analog-to-digital converter 18 under the conditionthat the face image browsing mode is specified by the user. In thiscase, step S4 is omitted, and the user's selection of the object imageis accepted by the operation of the image switching button 64, and thespecifying of the face image browsing mode can be accepted by theoperation of the face image browsing mode switch 62.

The electronic camera can be constituted like the modified example shownin FIG. 2B. In the example of FIG. 2B, after the signal processingcircuit 20 executes the color information converting process, the pixelcount converting process and the like on the image information (objectimage) from the analog-to-digital converter 18, the image information isstored in the memory 22. In the example of FIG. 2B, the imageinformation stored in the memory 22 is transmitted to the compressingcircuit 28 so as to be compressed as mentioned above and is transmittedto the signal processing circuit 46 for recognizing the face images. Theprocesses after step S2 are executed on the image information. In thiscase, step S4 is omitted.

When the face image browsing mode switch 36 is pressed down in step S6,the photographing mode or the reproducing mode is selected.

A first modified example in the first embodiment of the presentinvention is explained below.

In the first embodiment described above, only one object switchingbutton 66 is provided to the camera main body 50 a, and every time whenthe object switching button 66 is pressed down, the enlarged images areswitched to be displayed sequentially according to the raster order. Inthe first modified example of the first embodiment, four objectswitching buttons are provided, and desired enlarged images can beswitched to be displayed according to the user's selection.

The first modified example of the first embodiment is explained below.

FIG. 7 is a diagram illustrating a constitutional example of the objectswitching button according to the first modified example of the firstembodiment.

In FIG. 7, the object switching button 80 is composed of a switchingbutton (R) 80 a for switching an image into an image one frame after soas to display it, a switching button (L) 80 b for switching an imageinto an image one frame before so as to display it, a switching button(U) 80 c for enlarging an image, and a switching button (D) 80 d forreducing an image.

The camera main body 50 b provided with the object switching button 80is constituted as shown in FIG. 8. In the first modified example, sincethe part of the constitution other than the object switching button 80is the same as that in the first embodiment, like members are designatedby like reference numerals and the explanation thereof is omitted.

FIG. 9 is a flowchart explaining the operation for checking a face imagein the electronic camera according to the first modified example in thefirst embodiment. The processing operations in steps S21 to S25 aresimilar to those in the explanation related to steps S1 to S5 in theflowchart of FIG. 4.

When the power switch, not shown, is turned on, objects are photographedin step S21. The well-known face image recognizing process is executedin step S22. The regions of interest (ROI) of face images and the numberof objects' faces N1 on the screen are stored in the memory 22 in stepS23. The face image browsing mode switch 36 is pressed down in step S24,so that the face image browsing mode is executed. The face image in anupper left part of the screen is enlarged and displayed in the rasterorder in step S25, so that the face image N is set to “1”.

The camera is in the input standby state in step S26, and a button ofthe object switching buttons 80 which is pressed down is detected. Thatis to say, when the object switching button (L) 80 b is pressed down,the sequence goes to step S27, and when the object switching button (R)80 a is pressed down, the sequence goes to step S31. When the objectswitching button (U) 80 c is pressed down, the sequence goes to stepS36, and when the object switching button (D) 80 d is pressed down, thesequence goes to step S40.

In the case where the object switching button (L) 80 b is pressed downin step S27, a determination is made in step S28 whether the face imageN set in step S25 is N1. When N is “1”, the sequence goes to step S30,and the face image N=1 is set. Further, the sequence goes to step S35,and the region of interest relating to the image face of the firstobject is enlarged to be displayed on the liquid crystal display 60.

On the other hand, when N is not “1” in step S28, the sequence goes tostep S29, and N is decremented. As mentioned later, this is executed inorder to display an face image of the last object in the case where theface images of the second and after objects are displayed by the objectswitching button (R) 80 a. As a result, for example, the enlarged image74 c shown in FIG. 6B is switched into the enlarged image 74 b shown inFIG. 6A.

In the case where the object switching button (R) 80 a is pressed downin step S31, a determination is made in step S32 whether the face imageN is equal to the number N1 of the objects' faces on the screen set instep S25. When N is not equal to N1, the sequence goes to step S33, sothat N is incremented. The incremented face image of the N-th object isenlarged to be displayed on the liquid crystal display 60 in step S35.

On the other hand, when N=N1 is established in step S32, the sequencegoes to step S34, N is again set to “1”. This is because similarly tothe first embodiment, when the display reaches the number of the faceimages of the objects set in steps S23, the display returns to the faceimage of the first object. Therefore, at next step S35, the face imageof the N-th, namely, the first object is enlarged to be displayed on theliquid crystal display 60.

After the enlarged display in step S35, the sequence goes to step S26 sothat the camera is in the input standby state.

In the case where the object switching button (U) 80 c is pressed downin step S36 in the input standby state in step S26, the sequence goes tostep S37 so that a current enlargement scale X is compared with apredetermined maximum threshold value of the enlargement scale Thr_1.When the enlargement scale X is not more than the predetermined maximumthreshold value Thr_1 of the enlargement scale X, the sequence goes tostep S38 so that the current enlargement scale X is set to apredetermined scale A (for example, x 1.1). The sequence then goes tostep S44, and the face image displayed in step S25 or S35 is displayedat the enlargement scale X set in step S38 on the liquid crystal display35.

On the other hand, when the enlargement scale X exceeds thepredetermined maximum threshold value Thr_1 of the enlargement scale instep S37, the sequence goes to step S39, so that the maximum thresholdvalue of the predetermined enlargement Thr_1 is set as the currentenlargement scale X. The sequence then goes to step S44, and the faceimage displayed in step S25 or S35 is displayed at the enlargement scaleX set in step S38 on the liquid crystal display 60.

In the case where the object switching button (D) 80 d is pressed downin step S40 in the input standby state in step S26, the sequence goes tostep S41 so that the current enlargement scale X is compared with apredetermined minimum threshold value of the enlargement scale Thr_2.When the enlargement scale X is not less than the predetermined minimumthreshold value of the enlargement scale Thr_2, the sequence goes tostep S42 so that the current enlargement scale X is reduced to apredetermined scale B (for example, B=x 1/A). The sequence then goes tostep S44, and the face image displayed in step S25 or S35 is displayedat the enlargement scale X set in step S42 on the liquid crystal display60.

On the other hand, when the enlargement scale X is less than thepredetermined minimum threshold value of the enlargement scale Thr_2 instep S41, the sequence goes to step S43, and the predetermined minimumthreshold value of the enlargement scale Thr_2 is set as the currentenlargement scale X. The sequence goes to step S44, and the face imageto be displayed in step S25 or S35 is displayed at the enlargement scaleX set in step S43 on the liquid crystal display 60.

After the enlarged display in step S44, the sequence goes to step S26,and the camera is in the input standby state.

According to the first modified example in the first embodiment,similarly to the first embodiment described above, even in the casewhere a plurality of faces are photographed as objects, the objectswitching buttons 80 a to 80 d are operated so that the plural faceimages can be selectively switched so as to be displayed with theapproximately same size, and the face images can be changed into desiredsizes so as to be displayed.

In the first modified example, it goes without saying that the screenframes and the display regions can be displayed on the liquid crystaldisplay in the superimposing manner. A position on the photographedimage where the enlarged image displayed on the liquid crystal display60 is present can be easily checked by the display regions 78 a to 78 e.

In the first modified example, the size of the region of interest andthe coordinate start position are stored, but the center point of therange of interest, a point on the upper left of the region of interestor the like may be stored as the raster order. In this case, the rasterorder is different from the display order shown in FIG. 6.

A second modified example in the first embodiment of the presentinvention is explained below.

In the first embodiment and the first modified example, the face imageson the left part of the screen are sequentially enlarged to be displayedin the raster order. When, however, the face images are tried to bedisplayed precisely according to the raster order, this makes adifference between the raster order and the user's perception of theorder from upper left to lower right. For this reason, in the secondmodified example, an image on the monitor screen is divided into aplurality of divided regions, and the images on the regions aredisplayed according to the divided order.

The operation for checking face images in the electronic cameraaccording to the second modified example in the first embodiment of thepresent invention is explained with reference to the flowchart in FIG.10.

In the second modified example in the first embodiment, since theconstitution and the basic operation of the electronic camera are thesame as those in the first embodiment, like members are designated bylike numbers and the explanation thereof is omitted.

When the power switch, not shown, is turned on, objects are photographedin step S51. In this case, a plurality of people (in this case, five) 70a to 70 e are present as the objects as shown in FIG. 11. When theobjects are photographed in step S51, the face image recognizing processis executed in step S52. Similarly to step S2, the processes after stepS52 may be executed after specifying of the face image browsing mode isaccepted.

Indexes of the face images, the region of interest (ROI) and the numberN1 (=5) of the objects' faces on the screen are stored in the memory 22in step S53. For example, an image shown in FIG. 11 is displayed on theliquid crystal display 60. In this case, the five regions of interestfor the face images are designated by 72 a to 72 e for respective people70 a to 70 e. Information about them are stored. Further, the objectimage is divided into divided regions with indexes in step S54. In thiscase, the object image is divided into nine divided regions (1) 60 ₁ to(9) 60 ₉ as shown in FIG. 11. The divided regions (1) to (9) indicatethe numbers 1 to 9 given to the respective regions in FIG. 11.

In the case where the respective regions divided in step S54 includestart positions of the regions of interest for the face images,respectively, the indexes of the divided regions and the indexes of theface images are stored in step S55. In the case where one divided regionincludes two or more face images, a face image where the start positionof the region of interest is smaller has small index. For example, whenthe center points of the regions of interest are expressed by the rasterorder, in the case of the object image shown in FIG. 11, the face imagesof two people 70 b and 70 c are present in the divided region (2) 60 ₂.However, the region of interest 72 b whose start position is smaller hasan index smaller than that of the region of interest 72 c.

The face image browsing mode switch 62 is pressed down in step S56, sothat the face image browsing mode is executed. At next step S57, animage, where the index number of its divided region and the index numberof its face image are the smallest, is enlarged to be displayed, and theface image N is set to “1”. Thereafter, the sequence goes to step S58,and the camera is in the input standby state. Since the respectiveprocessing operations in steps S58 to S63 are similar to steps S6 to S11in the flowchart of FIG. 4, corresponding step numbers are referred toand the explanation thereof is omitted.

According to the second modified example, in the case where, forexample, the people 70 a to 70 e are present in the positions as shownin FIG. 11, the enlarged images in the regions of interest 72 a, 72 b,72 c, 72 d and 72 e are displayed sequentially in this order. As aresult, a difference between the order of actually displaying theenlarged images and the user's perception can be prevented.

Also in the second modified example, the screen frame and the displayregion can be displayed on the liquid crystal display in thesuperimposing manner. Further, in the second modified example, as to theraster order, the center point of the region of interest is used, but anupper left point of the region of interest or the like may be used.

In the second modified example, the object switching button 66 isoperated to switch the image of the object's face to another, asexplained above. Instead, four object switching buttons 80 a to 80 d mayof course be used to switch the image, as in the fist modified exampledescribed above.

SECOND EMBODIMENT

A second embodiment of the present invention is explained below.

In the first embodiment, the enlarged images are displayed in the rasterorder, but in the second embodiment, evaluated values of recognition ofthe objects' face images are calculated, so that the display of theenlarged images is switched according to the order of the evaluatedvalues.

In the second embodiment described below, since the constitution and thebasic operation of the electronic camera are the same as those in thefirst embodiment described above, like members are designate by likereference numerals and the explanation thereof is omitted.

The operation for checking face images in the electronic cameraaccording to the second embodiment of the present invention is explainedbelow with reference to the flowchart in FIG. 12.

When the power switch, not shown, is turned on, the objects arephotographed in step S71, and face images are recognized in step S72.The evaluated values of the face image recognition are calculated instep S73. Similarly to the case in step S2, the processes after step S72may be executed after the specifying of the face image browsing mode isaccepted.

The evaluated values are determined by the degree of similarity which isalso called a matching degree with respect to templates havingpredetermined facial shape in the recognizing method for recognizing aperson's face from an image. In the face image recognizing methodutilizing the matching degree, plural types of face-shaped templates areprepared, the matching degree between the templates and an image iscalculated according to normalization intercorrelation, and a templatehaving the highest matching degree is selected. When the highestmatching degree is not less than a predetermined threshold value, aregion in the selected template is determined as a face candidateregion. Such a recognizing method is disclosed in Jpn. Pat. Appln. KOKAIPublication No. 2004-240829.

In addition to the method of calculating the matching degree betweenface shape and a template, for example, an eye region may be extractedso that a face region is recognized in the face candidate region, or amouth, hair, a neck and the like are extracted from eye positioninformation so that a face region may be recognized.

The evaluated values of the face image, the regions of interest and thenumber N1 (=5) of the regions of interest are stored in the memory 22 instep S74. For example, in the case where the image shown in FIG. 5 isdisplayed on the liquid crystal display 60, the regions of interest forthe face image include the five regions of interest 72 a to 72 e forrespective people 70 a to 70 e. When the face image browsing mode switch62 is pressed down, the face image browsing mode is executed in stepS75. The face image with the highest evaluated value of the face imagerecognition calculated in step S73 is enlarged to be displayed in stepS76, and the face image N is set to 1. In this case, the face images Nhaving the higher evaluated values calculated in step S73 are set to“1”, “2”, . . . in this order.

Thereafter, the camera is in the input standby state in step S77. Thestate of the object switching button 66 is detected in step S78. Theprocesses in steps S77 and S78 are repeated until the object switchingbutton 66 is pressed down. In the case where the pressing-down of theobject switching button 66 is detected in step S78, the sequence goes tostep S79 so that a determination is made whether the set face image Nset in step S76 is N1.

The sequence goes to step S80 and the N is incremented until face imageN is equal to N1. The region of interest relating to the object's faceimage with N-th evaluated value is enlarged to be displayed on theliquid crystal display 60 in step S82. On the other hand, when the faceimage N is equal to N1 in step S79, the sequence goes to step S81, andthe face image N is set to “1” so that the first face image isdisplayed. Thereafter, when the original image is display in step S82,the camera is again in the input standby state in step S77.

According to the second embodiment, since the face images are switchedto be displayed sequentially in decreasing order of the evaluated valuesof the face image recognition, the high-precision face image can bechecked for the faces and a good photographed state.

Also in the second embodiment, it goes without saying that the screenframe and the display region can be displayed on the liquid crystaldisplay in the superimposing manner.

In the second embodiment, the face images are displayed on the liquidcrystal display sequentially in decreasing order of the evaluated valuesof the face image recognition, but the present invention is not limitedto this, and thus they may be displayed in increasing order of theevaluated values.

In the second embodiment, the face images are switched by the objectswitching button 66, but the present invention is not limited to this,and thus the four object switching buttons 80 a to 80 d may be used likethe first modified example of the first embodiment.

As to the evaluated value of the face image recognition, for example, anattention is paid to eye portions of objects, and eye shutting statesare evaluated by the method disclosed in Jpn. Pat. Appln. KOKAIPublication No. 2003-287784 so that the images may be displayed indecreasing order or increasing order of the evaluated values.

THIRD EMBODIMENT

A third embodiment of the present invention is explained below.

In the third embodiment, the enlarged face images are displayed in sucha manner that focus estimated positions are switched in order of beingcloser to the camera in cooperation with focus detection.

In the third embodiment, since the constitution and the basic operationof the electronic camera are the same as those in the first and thesecond embodiments, like members are designated by like referencenumerals and the explanation thereof is omitted.

The operation for checking face images in the electronic cameraaccording to the third embodiment of the present invention is explainedbelow with reference to a flowchart in FIG. 13.

When the power switch, not shown, is turned on, the well-known faceimage recognizing process is executed in step S91. The regions ofinterest and the number of regions of interest N1 on the face images arestored in step S92. The distance measuring unit 34 executes a focusdetecting process according to a well-known contrast method in step S93.The contrast method is disclosed in, for example, Japanese PatentPublication No. 2507144.

An estimated lens position (step number) of the photographing lens 12where the focus is the best, namely, the evaluated value is the largestin the regions of interest on the images is stored in the memory 22 instep S94. The focus position stored in step S94 is controlled as thelens position to be the best focus in step S95, and photographing iscarried out in step S96.

After photographing, when the face image browsing mode switch 62 ispressed down in step S97, the face image browsing mode is executed. Theregion of interest on the object's face image whose focus estimatedposition obtained in step S94 is the closest to the camera is enlargedto be displayed in step S98, and the face image N is set to “1”. In thiscase, as the distance from the camera is greater, the face images N are“1”, “2”, . . . according to the focus detecting process in step S93.

Thereafter, the camera is in the input standby state in step S99. Thestate of the object switching button 38 is detected in step S100. Theprocesses in steps S99 and S100 are repeated until the object switchingbutton 38 is pressed down. When the pressing-down of the objectswitching button 66 is detected in step S100, the sequence goes to stepS101, and a determination is made whether the face image N set in stepS98 is N1.

The sequence goes to step S102 and N is incremented until the face imageN is equal to N1. The face image of the object which is the N-th closestto the camera is enlarged to be displayed on the liquid crystal display60 in step S104. On the other hand, when the face image N is equal to N1in step S101, the sequence goes to step S103, and the face image N isset to “1” so that the first face image is displayed. Thereafter, whenthe original image is displayed in step S104, the camera is again in theinput standby state of step S99.

According to the third embodiment, since the objects are switched to bedisplayed sequentially in order such that the focus estimated positionsare closer to the camera, the faces and a good photographed state of thefaces can be checked easily from the face image.

Also in the third embodiment, it goes without saying that the screenframe and the display region can be displayed on the liquid crystaldisplay in the superimposing manner.

In the third embodiment, the face images are displayed in the order suchthat the focus estimated positions are closer to the camera, but on thecontrary the face images may be displayed according to the order suchthat the objects are farther from the camera.

Also in the third embodiment, the face images are switched by the objectswitching button 66, but the present invention is not limited to this,and thus the four object switching buttons 80 a to 80 d may be used likethe first modified example of the first embodiment.

A modified example of the third embodiment is explained below.

In the third embodiment, the order of the face images of the objects isdetermined according to their distances from the camera, but in themodified example of the third embodiment, the order of the face imagesof objects is determined according to the order such that object iscloser to their best focus positions of the camera.

In the modified example of the third embodiment described above, sincethe constitution and the basic operation of the electric camera are thesame as those in the first to the third embodiments, like members aredesignated by like reference numerals and the explanation thereof isomitted.

The operation for checking the face images in the electronic cameraaccording to the modified example in the third embodiment of the presentinvention is explained below with reference to a flowchart in FIG. 14.Since the processing operations in steps S111 to S117 in the flowchartof FIG. 14 are the same as those in steps S91 to S97 in the flowchart ofFIG. 13, only corresponding step numbers are referred to and theexplanation thereof is omitted.

The region of interest relating to the object's face image whose focusestimated position obtained in step S114 is the closest to the bestfocus is enlarged to be displayed in step S118, and the face image N isset to “1”. In this case, the face images N are set to “1”, “2”, . . .in this order such that the objects are farther from the best focusposition according to the focus detecting process in step S93.

Thereafter, the camera is in the input standby state in step S119. Thestate of the object switching button 66 is detected in step S120. Theprocesses in steps S119 and S120 are repeated until the object switchingbutton 66 is pressed down. When the pressing-down of the objectswitching button 66 is detected in step S120, the sequence goes to stepS121 so that a determination is made whether the face image N set instep S118 is N1.

The sequence goes to step S122 and N is incremented until the face imageN is equal to N1. The face image of the object in the focus positionwhich is the N-th closest from the best focus position is enlarged to bedisplayed on the liquid crystal display 60 in step S124. On the otherhand, when the face image N is equal to N1 in step S121, the sequencegoes to step S123, and the face image N is set to “1” so that the firstface image is displayed. Thereafter, when the original image isdisplayed in step S124, the camera is again in input standby state ofstep S119.

According to the modified example of the third embodiment, since theface images are switched to be displayed sequentially in the order suchthat the focus estimated positions are farther from the best focusposition of the camera, the faces and the good photographed state can bechecked easily on the face images.

Also in the modified example of the third embodiment, it goes withoutsaying that the screen frame and the display region can be displayed onthe liquid crystal display in the superimposing manner.

In the modified example of the third embodiment, the face images aredisplayed in the order such that the focus estimated positions areseparated from the best focus position of the camera, but on thecontrary the face images of the objects may be displayed in the ordersuch that the focus estimated positions approach the best focusposition.

Also in the modified example of the third embodiment, the face imagesare switched by the object switching button 66, but the presentinvention is not limited to this, and the four object switching buttons80 a to 80 d may be used similarly to the first modified example of thefirst embodiment.

The embodiments of the present invention have been explained above, butin addition to the above embodiments, the present invention can bevariously modified without departing from the scope of the presentinvention.

According to the present invention, the electronic camera, which has asimple interface for checking faces and a good photographed state when aplurality of faces are photographed as objects, can be provided.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

1. An image processing apparatus comprising: an image processing sectionwhich recognizes face images from an object image obtained by picking upan image of an object, determines regions of interest corresponding tothe recognized face images and performs an enlargement process; adisplay section which displays the face images obtained by the imageprocessing section; an image operating section which, when a pluralityof people are present in the object image, accepts an instruction forsequentially switching the face images to be displayed on the displaysection; and a control section which controls the face images so thatthey are sequentially switched to be displayed on the display sectionaccording to the instruction accepted by the image operating section;wherein the control section comprises: an acquiring section whichacquires information relating to a focusing position of the imageprocessing apparatus; and a display control section which controls faceimages closer to the focusing position indicated by the acquiredinformation to be displayed first, when the face images are sequentiallyswitched to be displayed on the display section.
 2. The image processingapparatus according to claim 1, wherein the display control sectioncontrols the face images to be displayed on the display section in anorder according to positions of the regions of interest of the faceimages with respect to a raster order.
 3. The image processing apparatusaccording to claim 2, wherein the image processing section divides theobject image into a plurality of divided regions, and the displaycontrol section controls the face images in the divided regions to bedisplayed on the display section in an order according to positions ofthe divided regions.
 4. The image processing apparatus according toclaim 1, wherein, when a plurality of people are present in the objectimage, the display control section controls the face images to bedisplayed on the display section in an order according to evaluatedvalues for recognizing the face images.
 5. The image processingapparatus according to claim 2, wherein the image operating sectionfurther comprises a change instructing section that changes a size ofthe face images to be displayed on the display section to a desiredsize.
 6. The image processing apparatus according to claim 1, whereinthe display control section controls positions on the object image wherethe face images to be displayed on the display section are present to bedisplayed on the display section in a superimposing manner.
 7. An imageprocessing apparatus comprising: an image processing section whichincludes a distance measuring section that detects a distance to anobject, recognizes face images from an object image obtained by pickingup an image of the object through an imaging lens, determines regions ofinterest corresponding to the recognized face images and performs anenlargement process; a display section which displays the face imagesobtained by the image processing section; a storage section which, whena plurality of people are present in the object image, stores lenspositions or estimated lens positions where focusing states of positionsof the recognized face images become best; an image operating sectionwhich accepts an instruction for sequentially switching the face imagesto be displayed on the display section according to information aboutthe lens positions or estimated lens positions stored in the storagesection; and a control section which controls the face images so thatthey are sequentially switched to be displayed on the display sectionaccording to the instruction accepted by the image operating section;wherein the control section comprises: an acquiring section whichacquires information relating to a focusing position of the imageprocessing apparatus; and a display control section which controls faceimages closer to the focusing position indicated by the acquiredinformation to be displayed first, when the face images are sequentiallyswitched to be displayed on the display section.
 8. The image processingapparatus according to claim 7, wherein the display control sectioncontrols the face images to be displayed on the display sectionsequentially starting from face images in positions where the distancemeasuring section determines that the distance is shorter.
 9. The imageprocessing apparatus according to claim 7, wherein the display controlsection controls the face images to be displayed on the display sectionsequentially according to an order such that the face images are closerto focusing positions determined by the distance measuring section. 10.The image processing apparatus according to claim 7, wherein the displaycontrol section controls positions on the object image where the faceimages displayed on the display section are present to be displayed onthe display section in a superimposing manner.
 11. An image processingmethod which recognizes face images from an object image obtained bypicking up an image of an object, and displays the face images obtainedby an image processing section that determines regions of interestcorresponding to the recognized face images and performs an enlargementprocess, said method comprising: acquiring information relating to afocusing position of the image processing apparatus; accepting aninstruction for sequentially switching the face images to be displayedon the display section when a plurality of people are present in theobject image; and first displaying face images closer to the focusingposition indicated by the acquired information, when the face imagesobtained by the image processing section are sequentially switched to bedisplayed.
 12. A computer-readable medium having stored thereon acomputer program which recognizes face images from an object imageobtained by picking up an image of an object, and displays the faceimages obtained by an image processing section that determines regionsof interest corresponding to the recognized face images and performs anenlargement process, said computer program controlling functions of:acquiring information relating to a focusing position of the imageprocessing apparatus; accepting an instruction for sequentiallyswitching the face images to be displayed on the display section when aplurality of people are present in the object image; and firstdisplaying face images closer to the focusing position indicated by theacquired information, when the face images obtained by the imageprocessing section are sequentially switched to be displayed.
 13. Anelectronic camera comprising: an image processing section whichrecognizes face images from an object image obtained by picking up animage of an object, determines regions of interest corresponding to therecognized face images and performs an enlargement process; a displaysection which displays the face images obtained by the image processingsection; an image operating section which, when a plurality of peopleare present in the object image, accepts an instruction for sequentiallyswitching the face images to be displayed on the display section; and acontrol section which controls the face images so that they aresequentially switched to be displayed on the display section accordingto the instruction accepted by the image operating section, wherein thecontrol section comprises: an acquiring section which acquiresinformation relating to a focusing position of the image processingsection; and a display control section which controls face images closerto the focusing position indicated by the acquired information to bedisplayed first, when the face images are sequentially switched to bedisplayed on the display section.